6-(substituted-hydroxyamidino)-penicillanic acids



3,322,781 6-(SUBSTITUTED-HYDROXYAMIDINO)- PENICHLLANIC ACIDS John Carl Godfrey, Syracuse, N.Y., assignor to Bristol- Myers Company, New York, N.Y., a corporation of Delaware N Drawing. Filed Oct. 18, 1963, Ser. No. 317,118 23 Claims. (Cl. 260-4067) This invention relates to novel antibacterial agents and, more particularly, to 6-(substituted-hydroxyamidino)penicillanic acids and their salts.

The compounds of the present invention are effective antibacterial agents against Gram-positive bacteria and are thus useful in the laboratory, e.g. to remove such organisms when found as contaminants.

There is thus provided, according to the present invention, the series of compounds of the formula in which R represents the side chain of any of the known penicillins, i.e. benzyl in the case of benzylpenicillins. It is this series which is named as 6-(substituted-hydroxyamidino)penicillanic acids. Nontoxic, pharmaceutically acceptable salts of these acids are included in this series.

Other known penicillins include those disclosed in US. Patents 2,941,995, 2,951,839, 2,996,501, 3,007,920, 3,025,- 290, 3,035,047, 3,040,032, 3,040,033, 3,041,332, 3,041,- 333, 3,043,831, 3,053,831, 3,071,575, 3,071,576, 3,- 082,204, 3,093,547 and 3,093,633; and in British patent specifications 874,414, 874,416, 876,516, 876,662, 877,120, 877,531, 878,233, 880,042, 880,400, 882,335, 888,110, 888,552, 889,066, 889,069, 889,070, 889,168, 889,231, 890,201, 891,279, 891,586, 891,938, 893,518, 894,247, 894,460, 896,072, 899,199, 900,666, 905,778, 906,383, 908,787, 914,419, 916,097, 916,204, 916,488, 920,176, 920,177, and in Belgian Patents 593,222, 595,171, 597,859, 602,494, 603,703, 609,039, 616,419 and 617,187 and in South African patent applications 60/2882, 60/3057, 60/3748, 61/ 1649, R6l/2751, 62/54, 62/4920, 63/1612 and 63/2423.

Preferred compounds of the present invention are those of the formulae 920,300, 921,513, 922,278, 924,037 and 925,281 I 8822,71 Patented May 30, 11967 wherein R represents hydrogen phenyl, fluoro, chloro, bromo, iodo, hydroxy, (lower)alkanoyloxy including especially acetoxy or (lower)alkoxy; X represents oxygen or sulfur; R and R each represent hydrogen, phenyl, benzyl, phenethyl or (lower)alkyl; R represents (lower)alkyl; R and R each represent (lower)a1ky1, (lower)alky1thio, benzylthio, cyclohexyl, cyclopentyl, cycloheptyl, benzyl, styryl, phenethyl, phenylp-ropyl, furyl, thienyl, naphthyl or Ar-; R represents (lower) alkylamino, di(lower)alkylamino, cycloalkylamino, having from 3 to 7 carbon atoms inclusive, allylamino, diallylamino, phenyl(lower)alkylamino, morpholino, lower(alkyl)morpholino, di(lower) alkylmorpholino, morpholino(lower)alkylamino, pyrrolidino, (lower) alkylpyrrolidino, di(lower) alkylpyrrolidino, N,N-hexamethyleneimino, piperidino, lower(alkyl)piperidino, di(lower) alkylpiperidino, 1,2,5,6-tetrahydropyridino, N-(lower) alkylpiperazino, N-p-henylpiperazino, N-(lower) alkyl (lower) alkylpiperazino, N-(lower) alkyl-di( lower) alkylpiperazino, furfurylamino, tetrahydrofurfurylamino, N-(lowcr)alkyl-N-furfurylamino, N-alkyl-N-anilino, or (lower)alkoxyanilino; Z Z and Z are each (lower) alkyl or Ar-; and Arrepresents the monovalent radical of the formula wherein R R and R are each a member selected from the group consisting of hydrogen, chloro, bromo, iodo, trifluoromethyl, phenyl, nitro, (lower)alkyl and (lower) alkoxy but only one R group may represent phenyl; and nontoxic, pharmaceutically acceptable salts thereof.

The nontoxic, pharmaceutically acceptable salts include metallic salts such as sodium, potassium, calcium and aluminum, the ammonium salt and substituted ammonium salts, e.g. salts of such nontoxic amines as trialkylamines, including triethylamine, procaine, dibenzylamine, N-benzyl-beta-phenethylamine, l-epihenamine, N,N'-dibenzylethylenediamine, dehydroabiethylamine, N,N'-bis-dehydroabiethylethylenediamine, N (lower)alkylpiperidines, e.g. N-ethylpiperidine, N-benzyldehydroabiethylamine and other amines which have been used to form salts with benzylpenicillin. The term (lower)a1kyl as used herein means both straight and branched chain aliphatic hydrocarbon radicals having from one to ten carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, hexyl, Z-ethylhexyl, heptyl, decyl, etc. Similarly, where the term ,(lower) is used as part of the description of another group, e.g. (lower)alkoxy it refers to the alkyl portion of such group which is therefore as de- A scribed above in connection with (lower)alkyl.

Preferred embodiments of the present invention are the NOH S CH3 wherein R represents (lower)alkyl;

wherein R represents (lower)alkyl;

NOH

C-CHa restricted series of compounds of the following formulae:

wherein R represents (lower)alkyl and R is hydrogen or chloro;

wheerin R is (lower) alkyl and R is hydrogen or chloro;

wherein R is (lower)alkyl; and the individual compounds of the following formulae NOH The starting material used in the process of the present invention is the hydroximic acid chloride (also called aldoxime chloride) or bromide having the formula NOH R-("l-X wherein X is chloro or bromo and wherein R has the meaning set forth above.

The products of the present invention are prepared by the reaction of 6-aminopenicillanic acid, preferably in the form of a neutral salt such as the sodium salt or the triethylamine salt, With the aldoxime chloride or bromide. The substituted 6-hydroxyamidinopenicillanic acid so produced is then isolated by the techniques used to recover a penicillin such as benzylpenicillin. The reaction is preferably carried out in an inert solvent for the two reagents, e.g., methylene chloride, at from -40 C. to the boiling point of the solvent. Use is made of about 0.3 to 3.0, and

preferably about 1.0, mole of 6-aminopenicillanic acid per mole of aldoxime chloride or bromide. The products are acids which can be used as such or converted to nontoxic, pharmaceutically acceptable salts.

The aldoxime chlorides and bromides used as starting materials in the present invention are prepared from the corresponding aldehyde oxime (by reaction with chlorine and bromine or nitrosyl chloride or nitrosyl bromide) according to the procedure reported in the literature for this type of compound, e.g., Rheinboldt et al., Annalen. 451, 161-178 (1927) and 460, 305-307 (1928); The Chemistry of the Carbon Compounds, Victor von Richter, third English edition, volume I page 329 and volume III, page 314, Elsevier Publishing Co., Inc., New York, NY. (1946); Perrold et al., J. Amer. Chem. Soc., 79, 462 (1957); The Organic Chemistry of Nitrogen, N. V. Sidgwick, Oxford University Press, 1942, pp. 199 and 235. These aldoxime chlorides and bromides are given various equivalent names, e.g., phenylhydroxamic acid chloride, benzaldoxime chloride, benzhydroximic chloride.

The aforesaid aldehyde oximes are easily prepared by known methods from the corresponding aldehydes. The aldehydes themselves are prepared as reported in the literature or by the use of the methods reported therein for similar compounds and particularly by reduction of the corresponding acids (which are often reported in the scientific literature and especially are described in the penicillin patents listed above) by standard techniques such as are described by Fieser and Fieser, Advanced Organic Chemistry, Reinhold Publishing Corporation, New York, N.Y., 1961, pp. 403, 823 and 824 and by Victor von Richter, The Chemistry of the Carbon Compounds, third English edition, Elsevier Publishing Co., Inc., New York, NY. (1946) in volume I, pp. 224229, volume II, pp. 122-124 and volume III, pp. 194, 264270.

The following examples will serve to illustrate this invention without limiting it thereto. All temperatures are given in degrees centigrade.

EXAMPLE 1 Potassium 6-(phanylhydroxyamidin0)penicillanate The triethylammonium salt of 6-aminopenicillanic acid was prepared by stirring a mixture of 10.8 g. of 6-aminopenicillanic acid (0.0500 mole), 200 ml. of methylene chloride, and 14.1 ml. of anhydrous triethylamine (0.100 mole) at 25 for 3 hours. The solution was cooled to -11 and a solution of 8.55 g. of benzaldoxime chloride (0.0550 mole) in 35 ml. of methylene chloride was added slowly, so that the maximum temperature during addition was 8. The reaction mixture was stirred at -l2 for one hour, and then filtered to remove a small amount of insoluble material. The filtrate, containing triethylammonium 6-(phenylhydroxyamidino)penicillanate, was extracted with two 100 ml. portions of ice water and the combined aqueous extracts were back-extracted with two 75 ml. portions of methylene chloride. The pH of the resulting aqueous solution was lowered from 8.2 to 2.9 by addition of 6 N sulfuric acid. The resulting turbid solution was then extracted with three 200 ml. portions of icecold ethyl acetate. (The aqueous phase was then set aside and eventually precipitated 4.45 g. of very pure 6-aminopenicillanic acid.) The combined ethyl acetate extracts, containing G-(phenylhydroxyamidino)penicillanic acid, were dried briefly over sodium sulfate and filtered into 10 g. of a 50% solution of potassium 2-ethylhexanoate in ether. The filtrate was flash-evaporated in vacuo to dryness at 33 and the residue was diluted with 800 ml. of dry ether, which caused 0.57 g. of a crystalline, pale yellow solid to separate. The product, 6-(phenylhydroxyamidino)penicillanate, was filtered off, dried, and found to have an indefinite melting point of 130150, in which range it turns to a deep red liquid. It gives an intense red-purple color when a dilute ethanolic solution of it is treated with a few drops of 1% ferric chloride in water.

This product was found to inhibit Staph. wureus Smith at concentrations of 12.5 mg./ml. or less.

Potassium 6-(3-nitrophenylhydroxyamidino)penicillanate The triethylammonium salt of 6-aminopenicillanic acid was prepared from 2.05 g. of 6-aminopenicillanic acid (0.00905 mole), 35.6 ml. of methylene chloride and 2.67 ml. (0.019 mole) of triethylamine by stirring for two and one-half hours at 25. A solution of 1.8 g. of m-nitrobenzaldoxime chloride (0.00897 mole) in 22.6 ml. of methylene chloride was added in three minutes to the resulting solution. The mixture was stirred at 25 for one hour and then refluxed for two minutes. Some insoluble solid was filtered off and the solvent was removed by flash distillation at 33. The residue, containing triethylammonium 6-(3'-nitrophenylhydroxyamidino)penicillanate, was dissolved in 56.5 ml. of cold water and the pH was adjusted to 6.5 by the addition of 6 N sulfuric acid. The solution was extracted with two 68 ml. portions of ice-cold ether, and acidified to pH 3.5 with 6 N sulfuric acid. The resulting turbidity was extracted with three portions of 60 ml. of ice-cold ethyl acetate. The combined ethyl acetate extracts, containing 6-(3-nitrophenylhydroxyamidino)penicillanic acid, were dried over sodium sulfate and filtered into 1.1 g. of a 50% solution of potassium 2-ethylhexanoate in ether. The filtrate was flashed dry at 33 and again flashed with two 300 ml. portions of ethyl acetate to remove traces of moisture. Addition of 500 ml. of dry ether to the residue yielded 640 mg. (16.9%) of potassium 6-(3-nitrophenylhydroxyamidino) penicillanate as a filterable solid which was shown by its infrared spectrum to be the desired penicillin.

Potassium 6-(4-nizrophenylhydroxyamidino) penicillanate The triethylammonium salt of 6-aminopenicillanic acid was prepared from 2.05 g. of 6-aminopenicillanic acid (0.00905 mole), 35.6 ml. methylene chloride and 2.67 ml. (0.019 mole) of triethylamine by stirring for two and one-half hours at 25. To the resulting solution, a solution of 1.8 g. of p-nitrobenzaldoxime chloride (0.00897 mole) in 30 ml. of methylene chloride was added during a 3-minute period. The mixture was stirred for 45 minutes at 25 and then refluxed for 2 minutes. Some insoluble solid was filtered off and the solvent removed by flash distillation at 33. The residue, containing triethylammonium 6- 4'-nitrophenylhydroxyamidino penicillanate, was dissolved in 56.5 ml. of ice water and the pH was adjusted to 7.0 with 6 N sulfuric acid. The solution was extracted with two 67.8 ml. portions of ice-cold ether and acidified to pH 3.5 with 6 N sulfuric acid. The resulting turbidity was extracted with three portions of 60 ml. of ice-cold ethyl acetate. The combined ethyl acetate extracts containing 6-(4-nitrophenylhydroxyamidino)penicillanic acid, were dried over sodium sulfate and filtered into 1.1 g. of 50% potassium 2-ethylhexanoate in ether solution. The filtrate was flashed dry at 33 and again flashed with two 300 ml. portions of ethyl acetate to remove traces of moisture. Addition of 500 ml. of dry ether to the residue yielded 640 mg. (16.9%) of potassium 6-(4'-nitr0phenylhydroxyamidino)penicillanate as a filterable solid which was shown by its infrared spectrum to be the desired penicillin. The reaction was repeated several times and the resulting solids were combined. These combined solids were purified by dissolving in a minimum amount of ethyl acetate with the aid of a few drops of water, charcoaling, filtering over diatomaceous earth, flashing dry at 33 and adding dry ether to the residue to give the product as a purified solid.

EXAMPLE 4 N,N-dibenzylethylenediamine 6-(benzylhydroxyamidin)penicillanate The triethylammonium salt of 6-aminopenicillanic acid was prepared from 10.8 g. of 6-aminopenicillanic acid (0.0500 mole), 250 ml. of methylene chloride, and 14.1 ml. (0.100 mole) of triethylamine by stirring for two hours at 25. The resulting solution was cooled to 8 and two-thirds of a solution of 8.50 g. of phenylacetaldoxime chloride (0.050 mole) in 150 ml. of dry methylene chloride was added. An additional 7.05 ml. (0.050 mole) of triethylamine was then added, followed by the rest of the oxime chloride solution. The maximum temperature during addition was 3.5. The mixture was stirred for 1.5 hours at 8. A trace of solid was then filtered off and the solvent was removed by flash distillation at 33. The residue, containing triethylammonium -(benzylhydroxyamidino)penicillanate, was dissolved in 250 ml. of ice water and the pH was adjusted to 6.6 by addition of 6 N sulfuric acid. The solution was extracted with three 200 ml. portions of ice-cold ether, filtered over diatomaceous earth to remove a trace of solid, and acidified to pH 3.6 with 6 N sulfuric acid. The resulting heavy turbidity was extracted with two 250 ml. portions of ice-cold ethyl acetate. The combined ethyl acetate extracts containing 6-(benzylhydroxyamidino)penicillanic acid, were dried over sodium sulfate and filtered into 6.5 g. of N,N-dibenzylethylenediamine. The filtrate was flashed dry at 33 and again flashed With 400 ml. of dry ethyl acetate to remove traces of moisture. The gummy, red residue was kneaded well with 600 ml. of dry acetone, Which dissolved the product but left behind as an insoluble residue a small amount of material which proved to be the dibenzylethylenediamine salt of decomposed penicillin. The acetone solution was flashed to a small volume at 33. Addition of 1 liter of dry ether yielded 60 g. (25%) of N,N'-dibenzylethylenediamine 6-(benzylhydroxyamidino)penicillanate as a filterable solid which was shown by its infrared spectrum to be the desired penicillin. It was purified by repeatedly dissolving in dry ethyl acetate, treating with decolorizing charcoal, filtering, flashing dry at 33, and triturating the residue with dry ether.

This product inhibited Staph. aureus Smith, D. pneumoniae, S. pyogenes digonnet f and S. enterz'lidis at concentrations of 0.25, 0.25, 0.13 and 25 meg/ml. respectively.

While various embodiments have been described in some detail, it will be understood that modifications can be made in the procedures described Without departing from the scope of the invention. Certain agents, compounds, or mixtures (e.g. acids, bases, solvents and the like) and other details described or equivalent to those described in relation to one procedure may be employed in connection with other procedures.

8 What is claimed is: 1. A compound of the formula wherein R represents (lower)alkyl. 2. A compound of the formula hydrogen.

3. A compound of the formula wherein R represents (lower)alkyl and R represents chloro.

4. A compound of the formula wherein R represents (lower)alkyl and R represents hydrogen.

5. A compound of the formula wherein R represents (lower)alkyl and R represents chloro.

6. A compound of the formula.

wherein R represents (lower)alkyl. 7. A compound of the formula NOH wherein R represents (lower)alkyl. 8. A compound of the formula CIia wherein R represents (lower)alkyl.

9. A compound of the formula NOH H3 15. A compound of the formula 17. A compound of the formula 18. A compound of the formula 19. A compound of the formula 20. A compound of the formula NOH CH3 21. A compound of the formula I NOH CH2 22. A compound of the formula 23. A member selected from the group consisting of the compounds of the formulae wherein R represents (lower)a lkyl;

wherein R represents (lower)-alkyl and R represents hydrogen;

wherein R represents (lower)alkyl and R represents chloro;

wherein R represents (lower)alkyl and R represents hydrogen;

wherein R represents (lower)alkyl and R represents chloro;

wherein R represents (lower) alkyl; wherein R represents (lower) alkyl;

I NOH )fi-R O=GNCH000H 0 wherein R represents 10wer(alky1).

No references cited.

NICHOLAS S. RIZZO, Primary Examiner.

HENRY R. JILES, Examiner.

JAMES W. ADAMS, JR., Assistant Examiner. 

23. A MEMBER SELECTED FROM THE GROUP CONSISTING OF THE COMPOUNDS OF THE FORMULAE 